Once again, I agree with Gmtech1.......and I'm getting sick of doing it!
Hey, if the solution worked for you, that's fine....we basically were agreeing that, that tech was wrong in stating that there was a sensor in the fan.....
I said that maybe there was a connection problem at the fan, but the other possibility was, the motor could have had a dead spot, and would occasionally not run when commanded on.....that's the only idea I can come up with, if the new fan runs ok now.......just glad you fixed the problem.....